Publishers.CombineLatest bug involving double Optionals

I think I found a bug in Combine.

Consider the following code:

import Combine

class Main {
    @Published var doubleOptional: String??
    var subscriptions: Set<AnyCancellable> = []
    
    init() {
        $doubleOptional
            .sink { print("value from direct sink: \(String(describing: $0))") }
            .store(in: &subscriptions)
        
        $doubleOptional
            .combineLatest(Just(0))
            .sink { print("value after combine latest: \(String(describing: $0.0))") }
            .store(in: &subscriptions)
    }
}

let main: Main = .init()

Output is

value from direct sink: nil
value after combine latest: Optional(nil)

when I think it should give the same value (nil).